As the mobile business continues to boom, the industry that serves app developers grows alongside it. Among these companies is San Francisco-based start-up Twilio, which offers customers—including Uber and CarGurus—notification technology, among other things.

Twilio's technology allows customers to send and receive text messages to users of their products or services and scale the solution for as much—or as little—as they need. The company also helps customers build their own virtual call centers.

Last year it partnered with Google to bring voice and messaging abilities to apps being developed with Google App Engine.

So far, Twilio has attracted more than $100 million in venture capital financing, including backing from Union Square Ventures and Bessemer Venture Partners. The company counts Home Depot, Walmart, and Airbnb among its other customers.

On the company's disruptive impact:

"Twilio is migrating a 150-year-old hardware industry to its future in software. As Amazon has done for technology infrastructure, as Salesforce has done for CRM, and as NetSuite has done for ERP, Twilio is changing how companies communicate with their customers."-Jeff Lawson, co-founder and CEO